The union argues that the lease of aircraft and cabin crew from Qatar Airways “breaches European regulations”.

Commenting on the announcement of the new strike period, Unite national officer Oliver Richardson said:

“Today’s announcement of a further escalation, underlines the determination of our members in their fight for better pay and against British Airways’ bullying behaviour.

“We are seeing strong support for the ongoing strike action. The time and money British Airways is spending on wet leasing aircraft and bullying striking cabin crew are resources which could easily settle this dispute.

“It’s high time British Airways stopped spending millions defending low pay and its bullying approach by negotiating a settlement to this long running dispute.”

BA says it is operating 99.5 per cent of its normal schedule during the current strike, and would “ensure all our customers reach their destinations”.